Reducing embodied ‘upfront’ carbon is the real challenge. Put simply, we need to focus on using less stuff and this will require bold and brave thinking, writes our regional director Richard Dowdall in an article published by The Developer.

Richard’s article follows his masterclass on the ‘material world’ and how we can make better material choices at the Festival of Place: Climate Resilience event. We’re proud supporters of the festival, which brings together professionals to learn and engage with best practice in creating sustainable and resilient places:

According to the UK Green Building Council’s Net Zero Whole Life Carbon Roadmap Progress report, embodied carbon emissions in the industry have reduced by just four per cent since the report’s baseline year in 2018, less than one quarter of the cut needed to stay on track.

A significant proportion of embodied carbon is ‘upfront carbon’ – a building’s embodied carbon relating to its construction and completion, before it is used. Upfront carbon involves the supply and transport of raw materials, manufacturing processes, the transport of manufactured materials to site, construction and installation. Reducing upfront carbon poses a real challenge for our sector.

Astonishing given the severity of the climate emergency we face, there is no legislation for embodied carbon in the built environment. Part Z, a proposed amendment to building regulations that would cap embodied carbon emissions during building work, is pending review and has made little political progress.

As a result, solutions to tackle carbon reduction are reliant on industry experts committed to making a difference. The UK Green Building Council is due to publish its Net Zero Carbon Building Standard in 2024, which will provide the industry with a series of guidance documents to help to achieve net zero carbon. Funders are also mandating climate resilient developments with robust sustainability targets. But we can’t solely rely on investors and institutions to steer carbon reduction, and our industry cannot wait for legislation to act.

So how can the industry make better material choices, and reduce embodied carbon in developments? Put simply, we must focus on using less stuff. If we can’t use less stuff, we must specify low carbon. And if we can’t use low carbon, the absolute last resort must be to offset carbon, to enable us to reach net zero.

When planning a future development, the first question all designers and developers should ask is can we build nothing? Can we challenge the initial brief, and fundamentally change it in some way?

If it’s not possible to hold off building entirely, we should build less, and refurbish, reuse or maximise the use of existing space. We must urgently repurpose existing materials and be bold and brave.

We must consider all options to build more efficiently and utilise everything within an existing structure for the benefit of that project. Can we use the foundations? Can any of the existing materials be reclaimed or recycled, or given to somebody else? Finally, we must look for ways to minimise project waste.

It might sound straightforward, but committing to using less is fundamental to the reduction of embodied carbon in the built environment. A monumental amount of carbon emissions has been produced to date and there is no way of taking it back. But we can find ways to use some of that carbon that has been captured and stored in existing materials and repurpose it for future development projects as an historical form of ‘carbon capture’.

The Mayfield Park project – which created 6.5 acres of new green space and Manchester’s first public park in 100 years – is a prime example of reuse. The site was previously a heavily industrial location, and a key part of the development involved the de-culverting of the River Medlock, which had been hidden under a concrete and iron culvert for more than 50 years. 

As civil and structural engineers on the site, we developed the design of the site infrastructure to reuse as much of the historic structures as possible, including the cast iron beams of the culvert for various new bridges within the park. This not only had cost and carbon savings but helped to preserve the site heritage.

Through recycling and reusing materials during the construction of the park alone, 230-240 tonnes of CO2 were saved. The development is setting a new standard for sustainability, helping Manchester meet its ambitious target of becoming zero carbon by 2038, twelve years ahead of the Government’s target for the rest of the UK.

In addition, the 140 new mature and semi-mature trees will remove more than three tonnes of CO2 (equivalent) from the atmosphere per year. The amount of carbon annually captured will increase over time as the trees grow. The re-use of water from the Victorian wells discovered during the construction of the park as a sustainable source of irrigation for trees and plants will also make a significant contribution, saving approximately one tonne of carbon per year and up to three million litres of water per year.

In the 20th century, quality, cost and time were the drivers for decision-making in any construction project. We searched for the materials and design solutions that could deliver a project in the shortest duration at the lowest cost for the highest quality output. Carbon is now a fourth pillar being factored into the process of design and development. Yet there’s more to be done.

We need to explore opportunities for low carbon design. Too often, the material choices we make are narrowed down too early and looked at through a lens of specification, which limits our field of vision. Instead, we must consider reuse the existing carbon in our built environment wherever possible and augment only where needed with low-carbon technology. Adopting this considered approach creates an environment where the project team can share best practice and support innovative solutions.

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Read Richard’s article in The Developer.